Tractor-trailer electrical connectors are known and are often referred to as “receptacles” or referred to by the applicable industry standard, (e.g. the SAE “J560 connector”). Though receptacles have been used for many years, existing receptacles are complicated to assemble with multiple stampings, pins and wires all held together by a myriad of fasteners. As a result, many receptacles used with tractor-trailers lack an easy-to-assemble modular design.
An example of a receptacle is shown in FIGS. 4, 5, and 9 of U.S. Pat. No. 6,450,833. FIGS. 4, 5, and 9, of U.S. Pat. No. 6,450,833 as well as the detailed description associated with FIGS. 4, 5, and 9 are incorporated herein by reference. Though the connector of U.S. Pat. No. 6,450,833 represents an acceptable solution to the problem of complicated assembly, it utilizes stampings and hooped wire ends held in place by multiple fasteners (such as the threaded studs designated “38” in FIG. 6). The specialized tooling and labor involved in manufacturing the receptacle of U.S. Pat. No. 6,450,833 are readily apparent, and hence, there is room for improvement.
The present invention uses a printed circuit board that need only be slid into place. Electrical connections are created by simply pushing electrical elements (such as circuit breakers and wires) into place on electrical pins. Electrical circuits are created on the printed circuit board via traces. Thus, a simplified and easy-to-assemble connector is created.
The present invention reduces installation labor and errors in assembly factory. Many trailer fleet owners request that the connectors used on their trailers provide electrical circuit overload protection. In those situations a separate in-line bank of circuit breakers contained in a junction box must be inserted separately from the SAE J560 connector, or another form of SAE J560 seven-way connector is supplied. The present invention integrates these circuit breakers into a standard size receptacle. The dimensions of the receptacle disclosed in FIGS. 3 and 6 (in inches) allow mounting compatibility with dimensions in wide use. Accordingly, the preferred embodiment is a seven-terminal receptacle configured to mate with an electrical connector extending from a highway tractor, according to an industry standard interface geometry (which in the preferred embodiment is the SAE J560 standard).
When circuit breakers are used, each harness lead must be connected to the appropriate terminal post of the circuit breaker for the correct circuit, external to the enclosure. This can lead to mistakes such as mismatched leads on the receptacle pin-load assignments, and short circuits or damaged leads when the receptacle assembly carrying the circuit breakers is mounted into the adapter box enclosure. It is even possible to by-pass the circuit protection if the harness lead is attached to the incorrect post of the breaker assembly.
The circuit breakers used are known as auto-resetting. These devices function by electrically opening the circuit if an attached electrical load exceeds the rated capacity of the device. This disconnect is accomplished by a heat sensitive bi-metal assembly that flexes to open the electrical contacts of the circuit breaker when a trigger temperature is reached. Unlike fuses, which are sacrificed by the function of protecting the circuit, the circuit breakers may be reset once the device cools and overload is repaired.
There are three general types of circuit breakers in use by the automotive and trucking industry. One type must be manually reset; yet another circuit breaker automatically resets after electrical power has been removed from the circuit. A third type of circuit breaker continually opens and closes as the device reacts to heat caused by the overloads (referred to as an “SAE Type I” circuit breaker). When an SAE Type I circuit breaker is overloaded, the vehicle's lights continually cycle on and off (blink) with the open/closed cycling of the circuit breaker. Thus, the vehicle remains visible to other traffic at night and the operator is alerted to the overload.
Unfortunately, if the operator fails to repair the cause of the overload, the SAE Type I circuit breaker will eventually fail due to mechanical fatigue or contact welding. It may fail in an electrically open or safe condition. However, if the device fails due to the welding of the contacts, the electrical circuit is permanently closed and the attached circuits are no longer protected. The present invention illustrated in the figures addresses these issues.
The receptacle constituting the presently preferred embodiment is delivered fully assembled and closed, ready to mount on the vehicle. No user work is required inside the enclosure. Installation amounts to positioning the assembly on mounting bolts pre-installed on the vehicle, tightening the mounting nuts, and snapping the harness connector into the mating 12-pin receiver (shown in FIG. 8) on the lower face of the box. This electrical connection is a commercially available device, providing a water-tight connection with alignment and locking features to ensure that the harness leads are properly oriented, seated, and sealed. This eliminates potential mis-wiring in the assembly plant or by the vehicle owner, and reduces the installation time.
Of course, the foregoing represents one of the advantages of the present invention; other advantages will be apparent to one of ordinary skill in the art after reading the following written description and the figures associated therewith.